I'm just on my way home from a great week of cave diving in Cave Country (North Central Florida). I had the opportunity of doing a beautiful dive at Eagles Nest with my good friend Wayne Kinard. Wayne was diving OC while I was diving my Hammerhead.
I was diving a 10/60 mix at a set point of 1.2. Even though I choose to dive OC in some cave diving situations, Eagles Nest is in my opinion, a dive that is more conducive to CCR. It's a very deep, large wide open cave with variable conditions that are effected by the tides. (Even though you won't find salt water in the cave, the tidal exchange will completely affect the viz from day to day.) We did a nice long dive with a total run time of 3 hours and 10 mins.
Although Eagles Nest is also the perfect cave in which to use a scooter, we chose to swim this time around. We dove the Upstream section and swam to the 1000 feet mark, which even though it doesn't sound like much, when you are swimming at 270 feet, a 1000 feet in and a 1000 feet back out is a pretty good work out! It took us 41 mins. to hit the 1000 feet mark where we turned the dive. at about 43 mins., I started to notice that I was getting a fair amount of water in the loop. I emptied it several times over the next few mins., but I kept getting more and more water! Thankfully, the Hammerhead is extremely flood resistant and tolerrent, and I knew that I could deal with a fair amount of water. Over the shoulder counter lungs and the radial scrubber that sits on top of a sizable spacer, combine to make for a substantial safety margin when it comes to water trapping.
When you are 40 mins. back in a cave at 270 deep, about the last thing in the world you really want to do is to test out your bailout planning efficiency! I was pretty confident that I was packing sufficient bailout, but not real excited about testing out my theory! Consequently, I was determined to complete the dive on the loop if at all possible. Because my buddy was on OC, I really wasn't too excited about having to share air with him if it turned out that my bailout was not sufficient, so I had even more motivation to stay on the loop as long as possible!
My work of breathing became a little more difficult as a portion of my scrubber became wet, but again due to the scrubber design, it was still functional. I just had to slow down a little bit so as not to over breath the scrubber at that point. A slight adjustment to my normal cave diving trim also helped keep the water out of the scrubber.
3 hours and 10 mins. later, I completed my deco and with a HUGE smile on my face surfaced still on the loop! When I later cleaned my unit, I found a couple of liters of water in both counter lungs, and in the canister. Never once did I even taste a hint of caustic cocktail. I was actually quite surprised at the volume of water!
So the big question that is now going through my mind is "Did I really have enough bailout? Given that I was diving with an OC buddy that really wouldn't have been in a position to do "team bailout", should I have staged more bailout then what I did?" I think the answer is that even though I theoretically had plenty of bailout, in this particular buddy team situation, one CCR and one OC, I will error on the side of extreme caution in the future. When I'm cave diving with my two sons on CCR, we dive as a team and carry loads of bailout between the team. When diving with an OC buddy, this type of dive does not lend itself to team bailout practices.
The conclusion I have come to is that I will be staging more bailout than my planning requires when doing a deep cave dive with an OC buddy. Although the Hammerhead is extremely flood tolerant, I will be hedging my bets in the future! A flooded CCR in a deep cave is a CCR divers worst nightmare! When in Cave Country I will occasionally see CCR divers way back in caves with nothing more than a couple of aluminum 40s. I wonder what would happen if they had a CO2 hit, or a flood and actually had to make it back out on these little tanks in what would surely be a very stressful situation? A little scary in my mind!
By the way, once I realized that I was taking on water, neither me or my buddy could figure out where it was coming from. After the dive, I noticed that it was coming from a slit in my mouthpiece. A simple problem that caused my a bit of concern during the dive!